1. Technical Field
The present invention relates to a display device and a head mounted image display apparatus.
2. Related Art
In the related art, there are known head mounted image display apparatuses mounted on the heads of users. A video display apparatus that has a waterproof structure is known as the head mounted image display apparatus (for example, see JP-A-2009-157290).
The video display apparatus disclosed in JP-A-2009-157290 includes a display element, a prism (light-guiding member), a casing that contains and holds the display element and the prism, and a packing. Of the elements, the packing is disposed to come into contact with the casing and a portion from which video light in the periphery of the prism is not reflected. Thus, the video display apparatus disclosed in JP-A-2009-157290 suppresses infiltration of a fluid such as water into the casing.
Incidentally, in the video display apparatus disclosed in JP-A-2009-157290, the light-guiding member guides image light to the eyes of a user. Therefore, it is necessary to dispose the light-guiding member within the casing (the video display apparatus) with high precision.
However, the configuration disclosed in JP-A-2009-157290 has a problem that the light-guiding member may not be disposed with high precision since a waterproof member is pressed when the waterproof member such as a packing is disposed between each surface of the light-guiding member and an external case forming the casing and is pressed, and thus the light-guiding member is moved from a position to which the image light can reliably be guided. Even when the position of an image projection unit is not changed with respect to the light-guiding member, an entire optical system is considered to be moved. In a binocular video display apparatus, a user can view an image. However, since right and left image display may be deviated, there is a problem that an image (in particular, a 3D image) may not be recognized accurately.
Since it is necessary for an external surface of the light-guiding member to guide image light to the eyes of the user while internally reflecting the image light, the waterproof member is not installed in a portion contributing to reflection of the light-guiding member. However, for example, in a case in which the waterproof member is not installed in the circumference of the light-guiding member, a fluid may be infiltrated into a frame member from a portion between the light-guiding member and the casing (external case).
However, even in a case in which the waterproof member is installed in a portion that does not contribute to reflection of the light-guiding member, there is a problem that a slight gap occurs between one surface of the light-guiding member and the external case due to tolerance and heat of a material of which the light-guiding member and the external case are formed, and thus a fluid such as water infiltrates into the casing via the gap due to capillarity.